Effect of InAs buffer layer thickness on physical properties of InAsBi heterostructures grown by MOCVD

The roles of Bi in InAs and InAsBi nanostructure growth

“…This is much higher than the reported values of the planar-grown InAsBi alloy (usually less than 10%). [23][24][25][26] Incorporating Bi into the InAs alloy is challenging due to the weak In-Bi bonding, large miscibility gap and lattice mismatch between InBi and InAs. 47 Any slight temperature change, III-V ratio, or As/Bi ratio may propose a large difference in Bi content, surface morphology and crystal quality.…”

“…21 Single crystal InAsBi alloy was first reported in 1989 by the Stringfellow group 22 using metal-organic chemical vapor deposition (MOCVD) with a Bi concentration of 2.6%. Various studies [23][24][25][26] have shown that Bi incorporation and the crystal quality are extremely sensitive to growth temperature, In/Bi flux ratio and In/As flux ratio. The large atomic radius difference between Bi and In leads to a miscibility gap and creates a small equilibrium solid solubility.…”

“…22,27 The non-incorporated Bi would also segregate onto the growth surface and even form a wetting layer (surfactant effects). 28 As a result, incorporating a large amount of Bi into the III-V alloys remains a challenge 26 clustering (In droplet formation) 26 and phase separation. 23,29 To resolve these problems, new epitaxy approaches and a comprehensive understanding of how Bi incorporates in InAsBi alloy are required.…”

“…22,27 The non-incorporated Bi would also segregate onto the growth surface and even form a wetting layer (surfactant effects). 28 As a result, incorporating a large amount of Bi into the III–V alloys remains a challenge 26 with the highest recorded Bi incorporation below 10%. Shalindar et al 25 reported InAsBi with Bi content of 6.45% using MBE, and recently Massoudi et al 26 reported 3.7% Bi concentration in InAsBi MOCVD growth.…”

“…28 As a result, incorporating a large amount of Bi into the III–V alloys remains a challenge 26 with the highest recorded Bi incorporation below 10%. Shalindar et al 25 reported InAsBi with Bi content of 6.45% using MBE, and recently Massoudi et al 26 reported 3.7% Bi concentration in InAsBi MOCVD growth. Due to the weak In–Bi bonding, increasing Bi incorporation is typically achieved by sacrificing crystal quality through lowering growth temperatures (<300 °C) and As fluxes, which led to problems such as alloy clustering (In droplet formation) 26 and phase separation.…”